1. Field of Invention
This invention relates to image generation, image detection, and the creation and use of a plurality of image sub-sections.
2. Background--Discussion of Prior Art
A variety of high resolution image sensors and display devices are widely employed in scanners, graphic display terminals, and cameras. Sometimes the cost of such imaging systems can be lowered by substituting two or more relatively inexpensive components for a single, more expensive one. For example, if a high resolution CCD (Charge Couple Device) area array is used in a camera, several smaller arrays may be used instead. These smaller arrays can be manufactured with higher yields and therefore at a lower cost. The relationships between yield, defect rate, and cost are made clearer by considering the following example: if there is a 0.5 probability that a 512.times.512 device will have at least one defect, then a 2048.times.2048 device will have a 0.9999847 probability of having at least one defect, i.e., on the average, only one defect free device will be produced out of 65536 units.
If several 512.times.512 components can be made to function as a single 2048.times.2048 device, the 50% yield on components can be maintained and, perhaps, manufacturing costs significantly decreased.
Other devices have characteristics which lend themselves to the application of this "divide and conquer" strategy. Large cathode ray tubes, for example, are expensive to manufacture because the supporting structure needed to maintain a large vacuum is expensive. Film-based photography represents another opportunity because film transport and development systems become disproportionately expensive as negative area is increased.
In order to use multiple imaging components, we must be able to convert an image to or from a plurality of composing image sub-sections. I call this process "tessellation" because the process is similar to creating a mosaic from sub-sections composed of individual porcelain tiles. When an object is scanned, an image of the object is broken down into a plurality of image sub-sections. When an image is projected, a plurality of image sub-sections are combined to form a single "object." For the remainder of this document, I will simplify much of the presentation by describing tessellation in terms of scanning systems. The analogous description of a tessellator used as a projector should be obvious.
Let us consider the physical position of these tessellated sub-sections created within a scanning system. If the sub-sections are physically adjacent, then the sensors must necessarily abut one another. Current technology has been able to produce buttable linear arrays, but they distort the image by producing discontinuities of one or more pixel between arrays. Area arrays which can be physically abutted are even more difficult to produce. Therefore, out of necessity, designs have separated the tessellated image sub-sections from one another. This can be accomplished in a variety of ways, using for example, multiple lenses or half-silvered mirrors. Heretofore, such systems have been costly, difficult to manufacture, difficult to align, and they have distorted the image in unacceptable ways. The present invention overcomes these disadvantages and thus demonstrates a tessellator that is inexpensive, easy to manufacture, and of a design whose image distortion is easily corrected. Alignment is generally easy to effect, but the means of doing so depends upon specific implementation details and system requirements.